Fabrication of Graded Structures in SiC-Reinforced Metal Matrix by Semisolid Powder Processing

Functionally graded structures offer innovative solutions to various challenges in materials engineering. However, the increasing demanding of FGSs has been hindered by the complex processing methods, high cost and composite control difficulties. By combining the concept of semisolid forming and powder metallurgy, semisolid powder processing provides a novel solution to the fabrication of FGS materials. In this paper, a two-layer FGS with one layer reinforced by SiC particles was fabricated with semisolid powder processing. The results indicate that, when the SiC particles are larger than the matrix powder, dense and strong parts can be formed. Smaller SiC particles can isolate the metal powders and resulting in porous and weak structures. Also, the roughness of the SiC particle surface affects interface bonding between SiC particles and Al-Si-Cu matrix phase. In summary, semisolid powder processing is capable of fabricating graded structures with promising microstructures and mechanical properties.